Volatile flavorings are added to tobacco products to achieve desirable organoleptic characteristics. See, for example, U.S. Pat. Nos. 3,006,347; 3,236,244; 3,344,796; 3,426,011; 3,972,335; 4,715,390; 5,137,034; 5,144,964; 5,479,949; 5,584,306; 5,724,998; 6,516,809; and 6,325,859, and commonly-owned International Publication No. WO 01/80671. The added flavorings are desirably volatilized when the tobacco products are smoked. The disclosure of U.S. Pat. No. 5,584,306 is hereby incorporated by reference.
Flavorings can be added to tobacco products during manufacturing. For example, menthol can be added to tobacco, and then tobacco rods can be formed from the mentholated tobacco. However, one problem with adding flavoring during manufacturing is that residual flavoring may undesirably remain in the manufacturing line which exacerbates the need for machine clean-up.
Another problem with adding flavorings is that flavorings can migrate and be lost during storage and distribution of tobacco products (prior to smoking of the tobacco products). The degree of migration depends on different factors including the flavoring's vapor pressure, the solubility of the flavoring in other components of the cigarette, and temperature and humidity conditions. Menthol is known to migrate to a great extent.
In addition to flavorings, various sorbent materials may be used in filters of smoking articles to remove selected constituents of tobacco smoke. Exemplary sorbent materials include activated carbons, molecular sieves, zeolites and mixtures thereof. However, volatile flavorants such as menthol tend to be drawn to and sorbed by the sorbent during the shelf-life of the smoking article.
Accordingly, there is interest in providing flavorings in tobacco products containing sorbent materials in a form less problematic to a manufacturing line, and providing reconstituted tobacco products that are less susceptible to migration prior to smoking.